Rainfall harvesting from roofs and backyards has been practiced in Jordan
for many years. However, this practiced has been decreases due to limited
rainfall and spread of public water supply system. Rainfall can be captured
from building roofs, courtyards and playground areas. Collected water
is stored in underground storage tanks and cisterns. In a larger scale,
rainfall harvesting can be achieved using pre-treated catchment and micro
catchment areas to increase the efficiency of runoff and maximize the
amount of collected rainfall. The objective of this research is to quantify
the efficiency of various surface treatment methods and its effect on
rainfall collection.

A laboratory experiment was conducted to estimate the runoff efficiency
using four surface treatment methods, two-rainfall intensities, two-rainfall
duration and two soils. Surface treatments were, wax treatment, plastic
cover and compaction plus a control. The two soils used in the experiments
were sand and loam soil. Results indicated that soil compaction had the
highest runoff efficiency followed by plastic cover, wax treatment and
natural soil. The runoff efficiency of sandy soil with rainfall intensity
of 3 mm/min and 10 min duration rainfall for compaction, plastic cover,
wax treatment, and natural soil were 79, 64, 45, and 20%, respectively.
The corresponding efficiencies for clay soils were 82, 71, 74, and 65%,
respectively. It has been concluded that little physical treatment of
soil surface such as compaction can enhance rainfall collection form backyard
and natural playgrounds and helps in increasing water supply in rural
areas.